Goerge Nesterczuk has gone two months without receiving a confirmation hearing.

A group of 16 unions representing federal employees wrote a letter to the leaders of a Senate panel urging them to reject the nomination of George Nesterczuk to be director of the Office of Personnel Management.

President Trump nominated Nesterczuk to lead the agency in May. Nesterczuk served in the George W. Bush, where he was one of the architects of the failed effort to introduce a performance-based pay model at the Defense Department.

His role in the creation of the National Security Personnel System, which failed after a legal battle, was chief among the reasons the unions said they opposed Nesterczuk’s nomination. Among those signing onto the letter were the American Federation of Government Employees; the National Federation of Federal Employees; and the American Federation of State, County and Municipal Employees.

“Based on [Defense’s] own internal report in 2008, the NSPS performance-based pay allocations and ratings were discriminatory based on race and the hierarchy of a worker’s position,” the unions wrote. “[This] discriminatory ratings system that Mr. Nesterczuk has yet to condemn is a precursor as to Mr. Nesterczuk’s laissez-faire views when it comes to equal treatment for all workers, regardless of race, sex or sexual orientation.”

The group also raised concerns about Nesterczuk’s past work as an adviser for the Ukrainian government on public administration issues, which appears to have occurred under Russian backed former President Victor Yanukovych. Yanukovych fled Ukraine in 2014, but has been back in the news lately as congressional investigators and Independent Counsel Robert Mueller investigate former Trump campaign manager Paul Manafort’s alleged ties to Russia.

“Mr. Nesterczuk should also be asked about his relationship with Paul Manafort, who was involved in presidential personnel appointments early in the Reagan administration when Mr. Nesterczuk was hired to a political position at OPM, and many years later worked for the Ukrainian government around or at the same time as Mr. Manafort,” they wrote. “Specifically, Mr. Nesterczuk should be asked if Mr. Manafort had a role in his hiring, and if he had any connections to his work on behalf of the Ukrainian government.”

Management groups were more optimistic about Nesterczuk’s nomination when it was first announced in May.

“[Nesterczuk] brings obvious strengths and knowledge to the position that are critically needed at a time when Congress and the public are calling for greater accountability and performance from the federal government,” said Senior Executives Association President Bill Valdez at the time.

But since then, there has been no movement in the Senate to advance his nomination. A confirmation hearing in the Senate Homeland Security and Governmental Operations Committee still has not been scheduled, and staff on the committee have not responded to repeated requests for comment.

By comparison, the committee has received 10 other nominees since Nesterczuk was formally nominated on May 25. Of those, two have been confirmed and the committee has had hearings and advanced the nominations of four others to the full Senate. Among those still awaiting hearings is Michael Rigas, Trump’s nominee to be deputy director of OPM, which was received by the committee on June 26.